108 IBM BladeCenter PS703 and PS704 Technical Overview and IntroductionBecause several simultaneous micro-partition migrations are supported by PowerVM LivePartition Mobility, it is conceivable to migrate the entire Shared-Processor Pool from oneserver to another.3.4.4 VIOSThe VIOS is part of all PowerVM Editions. The Virtual I/O partition allows the sharing ofphysical resources between logical partitions to allow more efficient use. The VIOS owns thephysical resources (SCSI, Fibre Channel, network adapters, and optical devices) and allowsclient partitions to share access to them, minimizing the number of physical adapters in thesystem. The VIOS eliminates the requirement that every partition owns a dedicated networkadapter, disk adapter, and disk drive. The VIOS supports OpenSSH for secure remote logins.It also provides a firewall for limiting access by ports, network services, and IP addresses.Figure 3-10 shows an overview of a VIOS configuration utilizing virtual SCSI and virtualEthernet.Figure 3-10 Architectural view of the VIOSBecause the VIOS is an operating system-based appliance server, redundancy for physicaldevices attached to the VIOS can be provided by using capabilities such as Multipath I/O andIEEE 802.3ad Link Aggregation.Installation of the VIOS partition is performed from a special system backup DVD that isprovided to clients who order any PowerVM edition. This dedicated software is only for theVIOS (and IVM in case it is used) and is only supported in special VIOS partitions. Threemajor virtual devices are supported by the Virtual I/O Server: Shared Ethernet Adapter Virtual SCSI Virtual Fibre Channel adapterThe Virtual Fibre Channel adapter is used with the NPIV feature, described in 3.4.9, “N_PortID Virtualization (NPIV)” on page 116.Shared Ethernet AdapterA Shared Ethernet Adapter (SEA) can be used to connect a physical Ethernet network to avirtual Ethernet network. The SEA provides this access by connecting the internal HypervisorVLANs with the VLANs on the external switches. Because the SEA processes packets atVirtual I/O Server HypervisorShared EthernetAdapterPhysical EthernetAdapterPhysical DiskAdapterVirtual I/O Client 1Virtual EthernetAdapterVirtual SCSIAdapterVirtual I/O Client 2Virtual EthernetAdapterVirtual SCSIAdapterVirtual EthernetAdapterVirtual SCSIAdapterPhysicalDiskPhysicalDiskExternal Network
